This invention relates to supplying an economizer fluid to an axially moveable non-orbiting scroll member.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a standard scroll compressor, a first scroll member has a base and a generally spiral wrap extending from the base. A second scroll member has a base and a generally spiral wrap that interfits with the base of the first scroll member. The second scroll member is driven to orbit relative to the first scroll. Compression occurs as refrigerant is sealingly entrapped between the wraps of the two scroll members as the second scroll member orbits relative to the first. Since scroll compressors have a greater efficiency than many types of compressors, they are desirable for many applications. However, scroll compressors also present design challenges.
One challenge faced by the designers of scroll compressors is that the scroll members must stay in contact with one another for the compression chamber to maintain a seal. However, as the refrigerant is compressed, a force is treated from the compressed refrigerant tending to force the two scroll members away from each other, thus reducing the efficiency of the seal. Scroll designers have addressed this separating force by tapping a compressed refrigerant behind one of the two scroll members to bias it towards the other, resisting the separating force and maintaining the seal. In one type of scroll compressor the tapped refrigerant is tapped to a chamber behind the orbiting scroll. In such compressors the non-orbiting scroll is typically fixed. In a second type of scroll compressor the tapped refrigerant is tapped to a chamber behind the non-orbiting scroll. In this type of s compressor the non-orbiting scroll is permitted to move axially, or float. A seal defines the chamber, and separates a discharge and suction pressure chamber.
Economizer cycles are known in refrigerant cycles. Essentially, an economizer cycle pre-cools a main refrigerant flow leaving a condenser and moving towards a primary expansion valve. To cool the main refrigerant flow, a smaller amount of refrigerant is tapped from the main flow and passed through an economizer heat exchanger. The main refrigerant flow is also passed through the economizer heat exchange where it is cooled by the tapped flow. The tapped refrigerant must be returned to the compressor.
In scroll compressors, it is preferred that the tapped refrigerant be returned to the compressor through the non-orbiting scroll. However, this has proven difficult in scroll compressors with a floating non-orbiting scroll, since the economizer injection port must extend through the floating non-orbiting scroll. The prior art has utilized a ribbed flexible connector that flexes during movement of the non-orbiting scroll. This flexible connector is fixed to the non-orbiting scroll, and to the housing. The rigid connection, and the use of the flexible connector is somewhat complex and expensive. Moreover, a rigid connection is somewhat unreliable in that it is subject to fracture with the relative movement.